Working vehicle periphery monitoring system and working vehicle

ABSTRACT

A working vehicle periphery monitoring system includes: image capturing devices attached to a working vehicle with a vessel and capturing the periphery of the working vehicle to output image information; a bird&#39;s eye image synthesizing unit synthesizing the image information to generate a bird&#39;s eye image information for displaying bird&#39;s eye images of the working vehicle and the periphery thereof; and a display control unit displaying at least one of a first bird&#39;s eye image obtained by superimposing a first vessel image including the vessel other than a part of the vessel at a rear side of the working vehicle on an area of the working vehicle in the bird&#39;s eye image and a second bird&#39;s eye image obtained by superimposing a second vessel image including all of the vessel on the area.

FIELD

The present invention relates to a technology of monitoring a peripheryof a working vehicle.

BACKGROUND

In a civil engineering work site or a quarry site of a mine, variousworking vehicles such as a dump truck and an excavator are operated.Particularly, a superjumbo working vehicle is used in a mine. Since sucha working vehicle has a vehicle width, a vehicle height, and alongitudinal length noticeably larger than those of a general vehicle,it is difficult for an operator to check and understand a peripheralcircumstance by a side mirror and the like. For this reason, there isproposed a device which monitors a periphery of a vehicle as a techniquefor assisting a running operation by helping the operator to simplyrecognize a vehicle periphery environment. For example, there isdisclosed a technique in which a graphic image or an outline imageshowing the entire dump truck at the bird's eye position transparentlyoverlaps bird's eye images based on outputs of a plurality of cameras(see Patent Literature 1).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Laid-open No.    2010-093605

SUMMARY Technical Problem

There is a case in which the operator of the working vehicle wants todisplay the entire working vehicle on the bird's eye image in order torecognize the relation between the working vehicle and the objectexisting therearound when operating the working vehicle. At this time,when the entire working vehicle is transparently displayed on the bird'seye image from the lower side of the working vehicle, there is apossibility that the operator may not easily recognize the state of theentire working vehicle. As a result, there is a possibility that theoperator (a service personnel when checking or repairing the workingvehicle) may not easily recognize the relation between the workingvehicle and the object existing therearound.

It is an object of the invention to provide an image which is easilyunderstood by the operator of the working vehicle when assisting therunning operation by using the bird's eye image in which the imagescaptured by a plurality of image capturing devices are synthesized witheach other.

Solution to Problem

According to the present invention, a working vehicle peripherymonitoring system that monitors a periphery of a working vehicleincluding a vehicle body frame which supports front and rear wheels anda vessel which protrudes toward a rear side of the vehicle body framethan the rear wheels to load freight thereon, the working vehicleperiphery monitoring system comprises: a plurality of image capturingdevices each of which is attached to the working vehicle and capturesthe periphery of the working vehicle to output a piece of imageinformation; a bird's eye image synthesizing unit that acquires aplurality pieces of the image information and synthesizes the acquiredimage information to generate bird's eye image information fordisplaying a bird's eye image of the working vehicle and the peripheryof the working vehicle on a display device; and a display control unitthat displays, on the display device, at least one of a first imageobtained by superimposing a first vessel image including at least thevessel other than a part of the vessel at the rear side of the workingvehicle on an area in which the working vehicle is present in the bird'seye image and a second image obtained by superimposing a second vesselimage including at least all of the vessel on an area in which thebird's eye image is present.

In the present invention, it is preferable that the display control unitswitches the display of the first image and the display of the secondimage based on an operation of an operator that operates the workingmachine.

In the present invention, it is preferable that the display control unitswitches the display of the first image and the display of the secondimage according to a state of the working vehicle.

In the present invention, it is preferable that the display control unitswitches the display of the first image and the display of the secondimage based on a running speed of the working vehicle.

In the present invention, it is preferable that the working vehicleincludes an object detection device that detects an object existingbehind the working vehicle, and the display control unit switches thedisplay of the first image and the display of the second image when theobject detection device detects the object.

In the present invention, it is preferable that the display control unitswitches the display of the first image and the display of the secondimage when a traveling mode of the working vehicle becomes a reversetraveling mode.

According to the present invention, a working vehicle peripherymonitoring system that monitors a periphery of a working vehicleincluding a vehicle body frame which supports front and rear wheels anda vessel which protrudes toward a rear side of the vehicle body framethan the rear wheels to load freight thereon, the working vehicleperiphery monitoring system comprises: a plurality of image capturingdevices each of which is attached to the working vehicle and capturesthe periphery of the working vehicle to output a piece of imageinformation; a bird's eye image synthesizing unit that acquires aplurality pieces of the image information and synthesizes the acquiredimage information to generate bird's eye image information fordisplaying a bird's eye image of the working vehicle and the peripheryof the working vehicle on a display device; and a display control unitthat displays, on the display device, at least one of a first imageobtained by superimposing a first vessel image including at least thevessel other than a part of the vessel at the rear side of the workingvehicle on an area in which the working vehicle is present in the bird'seye image and a second image obtained by superimposing a second vesselimage including at least all of the vessel on an area in which thebird's eye image is present, wherein the display control unit switchesthe display according to an operation of an operator that operates theworking machine or a state of the working vehicle.

In the present invention, it is preferable that the first vessel imageincludes the front and rear wheels displayed on the vessel, and thesecond vessel image includes the front and rear wheels displayed on thevessel.

In the present invention, it is preferable that the display control unitdisplays all of the front and rear wheels.

In the present invention, it is preferable that as the rear wheels, aplurality of vehicle wheels are displayed at each of left and rightsides of the vessel.

In the present invention, it is preferable that in the first vesselimage, a rear side of the vessel than an end of the rear wheel at therear side of the working vehicle is excluded.

According to the present invention, a working vehicle comprises: theworking vehicle periphery monitoring system.

According to the invention, it is possible to provide an image which iseasily understood by an operator of the working vehicle when assistingthe running operation by using the bird's eye image in which the imagescaptured by the plurality of image capturing devices are synthesizedwith each other.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a working vehicle according toan embodiment.

FIG. 2 is a diagram illustrating a structure and an interior of a cab 3which is included in the working vehicle according to the embodiment.

FIG. 3 is a diagram illustrating a periphery monitoring system 10according to the embodiment.

FIG. 4 is a perspective view of a dump truck 1 equipped with imagecapturing devices 11 to 16 which are included in the peripherymonitoring system 10 according to the embodiment.

FIG. 5 is a schematic diagram illustrating areas which are captured by aplurality of image capturing devices 11 to 16 and a bird's eye image 200which is generated based on the information of images captured by theplurality of image capturing devices 11 to 16.

FIG. 6 is a perspective view illustrating an arrangement of radardevices 21 to 26.

FIG. 7 is a diagram illustrating an image switching method using avirtual projection plane VP.

FIG. 8 is a conceptual diagram illustrating a bird's eye imageinformation 200I.

FIG. 9 is a diagram illustrating a first vessel image 200B1.

FIG. 10 is a diagram illustrating a second vessel image 200B2.

FIG. 11 is a diagram illustrating an example of a first bird's eye image201.

FIG. 12 is a diagram illustrating an example of a second bird's eyeimage 202.

FIG. 13 is a flowchart illustrating an example of a control thatswitches the display of the first bird's eye image 201 and the displayof the second bird's eye image 202.

DESCRIPTION OF EMBODIMENTS

A mode for carrying out the invention (embodiment) will be described indetail by referring to the drawings. The invention is not limited to thecontent described in the embodiment below. In the description below, thefront side, the rear side, the left side, and the right side are termsbased on an operator as an operator sitting in a driver seat. Forexample, the front side indicates the side where the visual line of theoperator sitting in the driver seat is directed and the side directedfrom the driver seat toward a handle operated by the operator. The rearside indicates the opposite side to the front side and the side directedfrom the handle toward the driver seat. The vehicle width direction ofthe working vehicle is identical to the left and right direction of theworking vehicle.

<Working Vehicle>

FIG. 1 is a perspective view illustrating a working vehicle according tothe embodiment. FIG. 2 is a diagram illustrating a structure and aninterior of the cab 3 which is included in the working vehicle accordingto the embodiment. In the embodiment, a self-propelled dump truck (alsocalled an off-highway truck) 1 as the working vehicle is a superjumbovehicle which is used for an operation in a mine. The type of the dumptruck is not limited. The dump truck 1 may be of, for example, anarticulated type or the like. The dump truck 1 includes a vehicle bodyportion 2, the cab 3, a vessel 4, front wheels 5, and rear wheels 6. Thevehicle body portion 2 includes an upper deck 2 b and a frame 2 fdisposed along the front and rear direction. Further, the dump truck 1includes a periphery monitoring system which monitors the peripherythereof and displays the result. The periphery monitoring system will bedescribed in detail later.

In the embodiment, the dump truck 1 drives an electric motor by thepower generated when an internal combustion engine such as a dieselengine drives a generator, so that the rear wheels 6 are driven. In thisway, the dump truck 1 is of a so-called electric driving type, but thedriving type of the dump truck 1 is not limited thereto. For example,the dump truck 1 may transmit the power of the internal combustionengine to the rear wheels 6 through a transmission so as to drive therear wheels or may drive an electric motor by the power supplied througha trolley from a line so as to drive the rear wheels 6 by the electricmotor.

The frame 2 f supports power generating mechanisms such as the internalcombustion engine and the generator and auxiliary machines thereof. Theleft and right front wheels 5 (only the right front wheel is illustratedin FIG. 1) are supported by the front portion of the frame 2 f. The leftand right rear wheels 6 (only the right rear wheel is illustrated inFIG. 1) are supported by the rear portion of the frame 2 f. Each of thefront wheels 5 and the rear wheels 6 has a diameter of about 2 m(meters) to 4 m (meters). As for the rear wheels 6, the inside positionof the vessel 4 in the width direction or the outside position of thevessel 4 in the width direction is disposed substantially at the sameposition as the outside of the rear wheel 6 in the width direction. Theframe 2 f includes a lower deck 2 a and the upper deck 2 b. In this way,the dump truck 1 which is used in a mine is formed as a double deckstructure with the lower deck 2 a and the upper deck 2 b.

The lower deck 2 a is attached to the lower portion of the front surfaceof the frame 2 f. The upper deck 2 b is disposed above the lower deck 2a. A movable ladder 2 c which is used to elevate the cab 3, for example,is disposed below the lower deck 2 a. An inclined ladder 2 d is disposedbetween the lower deck 2 a and the upper deck 2 b so that the operatormoves therebetween. Further, a radiator is disposed between the lowerdeck 2 a and the upper deck 2 b. A palisade guardrail 2 e is disposed onthe upper deck 2 b. In the embodiment, the ladder 2 c and the inclinedladder 2 d are set as a part of the upper deck 2 b and the lower deck 2a.

As illustrated in FIG. 1, the cab (operating room) 3 is disposed on theupper deck 2 b. The cab 3 is disposed on the upper deck 2 b so as to beshifted to one side in the vehicle width direction in relation to thecenter in the vehicle width direction. Specifically, the cab 3 isdisposed on the upper deck 2 b so as to be positioned at the left sidein the vehicle width direction in relation to the center. Thearrangement of the cab 3 is not limited to the left side in relation tothe center in the vehicle width direction. For example, the cab 3 may bedisposed at the right side in the vehicle width direction in relation tothe center, and may be disposed at the center in the vehicle widthdirection. Operation members such as a driver seat, a handle, a shiftlever, an accelerator pedal, and a brake pedal are arranged inside thecab 3.

As illustrated in FIG. 2, the cab 3 includes a ROPS (Roll-OverProtection System) with a plurality of (in the embodiment, four) pillars3 a, 3 b, 3 c, and 3 d. The ROPS protects the operator inside the cab 3if the dump truck 1 rolls over. The driver of the dump truck 1 drivesthe dump truck in a state where a road shoulder at the left side of thevehicle body portion 2 may be easily checked, but the operator's headneeds to be largely moved so as to check the periphery of the vehiclebody portion 2. Further, the upper deck 2 b is provided with a pluralityof side mirrors (not illustrated) which are to check the periphery ofthe dump truck 1. Since the side mirrors are arranged at positions awayfrom the cab 3, the driver needs to largely move his/her head even whenchecking the periphery of the vehicle body portion 2 using the sidemirrors.

As illustrated in FIG. 2, a driver seat 31, a handle 32, a dash cover33, a wireless device 34, a radio receiver 35, a retarder 36, a shiftlever 37, a trainer seat 38, a controller (to be described later indetail) as a monitoring control device not illustrated in FIG. 2, amonitor 50, an accelerator pedal, and a brake pedal are provided insidethe cab 3. The monitor 50 which is assembled in the dash cover 33 isillustrated in FIG. 2. However, the invention is not limited thereto,and for example, the monitor 50 may be provided on the dash cover 33 ormay be provided so as to be suspended from the ceiling inside the cab 3.That is, the monitor 50 may be provided at a position where the operatorcan see the monitor 50. Furthermore, the controller not illustrated inFIG. 2 is a part of a periphery monitoring system 10 to be describedlater. The shift lever 37 is a device which causes the operator of thedump truck 1 to change the traveling direction of the dump truck 1 orthe speed gear thereof.

The vessel 4 illustrated in FIG. 1 is a container which loads freightsuch as crushed stones thereon. The rear portion of the bottom surfaceof the vessel 4 is rotatably connected to the rear portion of the frame2 f through a rotary pin. The vessel 4 may take a loading posture and astanding posture by an actuator such as a hydraulic cylinder. Asillustrated in FIG. 1, the loading posture indicates a posture in whichthe front portion of the vessel 4 is positioned at the upper portion ofthe cab 3. The standing posture indicates a posture in which the freightis discharged and the vessel 4 is inclined rearward and downward. Whenthe front portion of the vessel 4 rotates upward, the vessel 4 changesfrom the loading posture to the standing posture. The vessel 4 includesa flange portion 4F formed at the front portion thereof. The flangeportion 4F is called a protector and extends to the upper side of thecab 3 so as to cover the cab 3. The flange portion 4F which extends tothe upper side of the cab 3 protects the cab 3 from the collision withcrushed stones and the like.

<Periphery Monitoring System>

FIG. 3 is a diagram illustrating the periphery monitoring system 10according to the embodiment. FIG. 4 is a perspective view of the dumptruck 1 equipped with image capturing devices 11 to 16 which areincluded in the periphery monitoring system 10 according to theembodiment. FIG. 5 is a schematic diagram illustrating areas which arecaptured by a plurality of image capturing devices 11 to 16 and a bird'seye image 200 which is generated based on the information of the imagescaptured by the plurality of image capturing devices 11 to 16. The areaswhich are captured by the plurality of image capturing devicesillustrated in FIG. 5 are areas taking the ground surface as reference.As illustrated in FIG. 3, the periphery monitoring system 10 includes aplurality of (in the embodiment, six) image capturing devices 11, 12,13, 14, 15, and 16, a plurality of (in the embodiment, eight) radardevices 21, 22, 23, 24, 25, 26, 27, and 28, the monitor 50, and acontroller 100 as a monitoring control device. Furthermore, in theembodiment, the periphery monitoring system 10 may not be essentiallyprovided with the radar devices 21, 22, 23, 24, 25, 26, 27, and 28.

<Image Capturing Device>

The image capturing devices 11, 12, 13, 14, 15, and 16 are attached tothe dump truck 1. The image capturing devices 11, 12, 13, 14, 15, and 16are, for example, wide dynamic range (WDR) cameras. The wide dynamicrange camera is a camera that has a function of brightly correcting adark portion while maintaining a bright portion at a visible level andadjusting the entire portion so as to be visible.

The image capturing devices 11, 12, 13, 14, 15, and 16 capture theperiphery of the dump truck 1 and output the result as an imageinformation. In the description below, the image capturing device 11 isappropriately referred to as a first image capturing device 11, theimage capturing device 12 is appropriately referred to as a second imagecapturing device 12, the image capturing device 13 is appropriatelyreferred to as a third image capturing device 13, the image capturingdevice 14 is appropriately referred to as a fourth image capturingdevice 14, the image capturing device 15 is appropriately referred to asa fifth image capturing device 15, and the image capturing device 16 isappropriately referred to as a sixth image capturing device 16. Further,when there is no need to distinguish these image capturing devices,these image capturing devices are appropriately referred to as the imagecapturing devices 11 to 16.

As illustrated in FIG. 4, six image capturing devices 11 to 16 arerespectively attached to the outer peripheral portion of the dump truck1 so as to capture the images in the periphery of the dump truck 1 by360°. In the embodiment, each of the image capturing devices 11 to 16has a viewing range of 120° (60° at each of the left and right sides) inthe left and right direction and 96° in the height direction, but theviewing range is not limited thereto. Further, the respective imagecapturing devices 11 to 16 are indicated by the arrows in FIG. 4, andthe directions indicated by the arrows indicate the directions in whichthe respective image capturing devices 11 to 16 face.

As illustrated in FIG. 4, the first image capturing device 11 isattached to the front surface of the dump truck 1. Specifically, thefirst image capturing device 11 is disposed at the upper end of theinclined ladder 2 d, and more specifically, the lower side of thelanding portion of the uppermost stage. The first image capturing device11 is fixed through the bracket which is attached to the upper deck 2 bso as to face the front side of the dump truck 1. As illustrated in FIG.5, the first image capturing device 11 captures a first area 11C in thearea existing in the periphery of the dump truck 1 and outputs a firstimage information as an image information. The first area 11C is an areawhich is extended toward the front side of the vehicle body portion 2 ofthe dump truck 1.

As illustrated in FIG. 4, the second image capturing device 12 isattached to one side portion of the front surface of the dump truck 1.Specifically, the second image capturing device 12 is disposed at theright portion of the front surface of the upper deck 2 b. The secondimage capturing device 12 is fixed through the bracket attached to theupper deck 2 b so as to face the diagonally forward right side of thedump truck 1. As illustrated in FIG. 5, the second image capturingdevice 12 captures a second area 12C in the area existing in theperiphery of the dump truck 1 and outputs a second image information asan image information. The second area 12C is an area which is extendedtoward the diagonally forward right side of the vehicle body portion 2of the dump truck 1.

As illustrated in FIG. 4, the third image capturing device 13 isattached to the other side of the front surface of the dump truck 1.Specifically, the third image capturing device 13 is disposed at theleft portion of the front surface of the upper deck 2 b. Then, the thirdimage capturing device 13 is disposed so as to be bilaterally symmetricto the second image capturing device 12 about the axis passing thecenter of the dump truck 1 in the vehicle width direction. The thirdimage capturing device 13 is fixed through the bracket attached to theupper deck 2 b so as to face the diagonally forward left side of thedump truck 1. As illustrated in FIG. 5, the third image capturing device13 captures a third area 13C in the area existing in the periphery ofthe dump truck 1 and outputs a third image information as an imageinformation. The third area 13C is an area which is extended toward thediagonally forward left side of the vehicle body portion 2 of the dumptruck 1.

As illustrated in FIG. 4, the fourth image capturing device 14 isattached to one side surface of the dump truck 1. Specifically, thefourth image capturing device 14 is disposed at the front portion of theright side surface of the upper deck 2 b. The fourth image capturingdevice 14 is fixed through the bracket attached to the upper deck 2 b soas to face the diagonally backward right side of the dump truck 1. Asillustrated in FIG. 5, the fourth image capturing device 14 captures afourth area 14C in the area existing in the periphery of the dump truck1 and outputs a fourth image information as an image information. Thefourth area 14C is an area which is extended toward the diagonallybackward right side of the vehicle body portion 2 of the dump truck 1.

As illustrated in FIG. 4, the fifth image capturing device 15 isattached to the other side surface of the dump truck 1. Specifically,the fifth image capturing device 15 is disposed at the front portion ofthe left side surface of the upper deck 2 b. Then, the fifth imagecapturing device 15 is disposed so as to be bilaterally symmetric to thefourth image capturing device 14 about the axis passing the center ofthe dump truck 1 in the vehicle width direction. As illustrated in FIG.5, the fifth image capturing device 15 captures a fifth area 15C in thearea existing in the periphery of the dump truck 1 and outputs a fifthimage information as an image information. The fifth area 15C is an areawhich is extended toward the diagonally backward left side of thevehicle body portion 2 of the dump truck 1.

As illustrated in FIG. 4, the sixth image capturing device 16 isattached to the rear portion of the dump truck 1. Specifically, thesixth image capturing device 16 is disposed above an axle housingconnecting two rear wheels 6 and 6 at the rear end of the frame 2 f andnear the rotary shaft of the vessel 4. The sixth image capturing device16 is fixed toward the rear side of the dump truck 1 through the bracketwhich is attached to a crossbar connecting the left and right frames 2f. As illustrated in FIG. 5, the sixth image capturing device 16captures a sixth area 16C in the area existing in the periphery of thedump truck 1 and outputs a sixth image information as an imageinformation. The sixth area 16C is an area which is extended toward therear side of the vehicle body portion 2 of the dump truck 1.

By using the above-described six image capturing devices 11 to 16, theperiphery monitoring system 10 according to the embodiment may capturethe images in the entire circumference of the dump truck 1 by 360° andacquire the image information as illustrated in FIG. 5. Six imagecapturing devices 11 to 16 transmit the first image information to thesixth image information as the respectively captured image informationto the controller 100 illustrated in FIG. 3.

The first image capturing device 11, the second image capturing device12, the third image capturing device 13, the fourth image capturingdevice 14, and the fifth image capturing device 15 are provided in theupper deck 2 b which exists at the relatively high position. For thisreason, the controller 100 may obtain an image which is seen from thebird's eye position toward the ground surface by the first imagecapturing device 11 to the fifth image capturing device 15 and hence maycapture an object such as a vehicle existing on the ground surface in abroad range. Further, even when the viewing point is changed uponcausing the controller 100 to generate the bird's eye image 200illustrated in FIG. 5 from the first image information to the sixthimage information acquired by the first image capturing device 11 to thesixth image capturing device 16, the deformation degree of thethree-dimensional object is suppressed since the first image informationto the fifth image information in the first image information to thesixth image information are information items captured from the bird'seye position.

<Radar Device>

FIG. 6 is a perspective view illustrating an arrangement of the radardevices 21 to 28. In the embodiment, each of the radar devices 21, 22,23, 24, 25, 26, 27, and 28 (hereinafter, referred to as appropriateradar devices 21 to 28) as the object detecting device is a ultra wideband (UWB) radar which has, for example, the orientation of 80° (40° inthe left and right directions) and a maximum detection distance of 15 mor more. The radar devices 21 to 28 detect a position (relativeposition) of the object existing in the periphery of the dump truck 1relative to the dump truck 1. The respective radar devices 21 to 28 areattached to the outer peripheral portion of the dump truck 1 as in theimage capturing devices 11 to 16. Further, the respective radar devices21 to 28 are indicated by the arrows in FIG. 6, and the directionindicated by the arrows indicate the directions of the detection rangesof the respective radar devices 21 to 28.

As illustrated in FIG. 6, the radar device 21 (which is appropriatelyreferred to as the first radar device 21) is disposed at the frontsurface of the vehicle body portion 2 in the lower deck 2 a disposed atthe height of about 1 m from the ground surface and the slightly rightside in relation to the center of the vehicle body portion 2 in thevehicle width direction. The detection range of the first radar device21 becomes a range which is extended toward the diagonally forward leftside from the front side of the vehicle body portion 2 of the dump truck1.

As illustrated in FIG. 6, the radar device 22 (which is appropriatelyreferred to as the second radar device 22) is disposed at the frontsurface of the vehicle body portion 2 in the lower deck 2 a and theslightly left side in relation to the center of the vehicle body portion2 in the vehicle width direction. That is, the second radar device 22 isdisposed at the left side of the first radar device 21 so as to beadjacent to the first radar device 21. The detection range of the secondradar device 22 becomes a range which is extended toward the diagonallyforward right side from the front side of the vehicle body portion 2 ofthe dump truck 1.

As illustrated in FIG. 6, the radar device 23 (which is appropriatelyreferred to as the third radar device 23) is disposed near the front endof the right side surface of the lower deck 2 a. The detection range ofthe third radar device 23 becomes a range which is extended rightwardfrom the diagonally forward right side of the vehicle body portion 2 ofthe dump truck 1.

As illustrated in FIG. 6, the radar device 24 (which is appropriatelyreferred to as the fourth radar device 24) is disposed near the rightend at the middle height position between the lower deck 2 a and theupper deck 2 b at the side portion of the vehicle body portion 2. Thedetection range of the fourth radar device 24 becomes a range which isextended backward from the right side of the vehicle body portion 2 ofthe dump truck 1.

As illustrated in FIG. 6, the radar device 25 (which is appropriatelyreferred to as the fifth radar device 25) is disposed above the axlethat transmits the driving force to the left and right rear wheels 6 ofthe dump truck 1 below the vessel 4. The detection range of the fifthradar device 25 becomes a range which is extended backward from thediagonally backward right side of the vehicle body portion 2 of the dumptruck 1.

As illustrated in FIG. 6, the radar device 26 (which is appropriatelyreferred to as the sixth radar device 26) is disposed near the rightside of the fifth radar device 25 above the axle as in the fifth radardevice 25. The detection range of the sixth radar device 26 becomes arange which is extended backward from the diagonally backward left sideof the vehicle body portion 2 of the dump truck 1 so as to intersect thedetection range of the fifth radar device 25.

As illustrated in FIG. 6, the radar device 27 (which is appropriatelyreferred to as the seventh radar device 27) is disposed near the leftend at the middle height position between the lower deck 2 a and theupper deck 2 b at the side surface of the vehicle body portion 2. Thatis, the radar device is disposed so as to be bilaterally symmetric tothe fourth radar device 24 about the center axis of the vehicle bodyportion 2 in the vehicle width direction. The detection range of theseventh radar device 27 becomes a range which is extended backward fromthe left side of the vehicle body portion 2 of the dump truck 1.

As illustrated in FIG. 6, the radar device 28 (which is appropriatelyreferred to as the eighth radar device 28) is disposed near the frontend of the left side surface of the lower deck 2 a. That is, the radardevice is disposed so as to be bilaterally symmetric to the third radardevice 23 about the center axis of the vehicle body portion 2 in thevehicle width direction. The detection range of the eighth radar device28 becomes a range which is extended leftward from the diagonallyforward left side of the vehicle body portion 2 of the dump truck 1.

Eight radar devices 21 to 28 may detect the relative position betweenthe dump truck 1 and objects in the detection range in the entireperiphery of 360° of the dump truck 1. Eight radar devices 21 to 28transmit the relative position information representing the relativeposition between the respectively detected objects and the dump truck 1to the controller 100. In this way, the plurality of (eight) radardevices 21 to 28 are provided in the vehicle body portion 2 so as todetect the object existing in the entire periphery of the vehicle bodyportion 2.

<Controller>

The controller 100 illustrated in FIG. 3 displays the existence of theobject in the periphery of the dump truck 1 as the bird's eye image 200captured by the image capturing devices 11 to 16 and the radar devices21 to 28 and notifies the existence of the object to the operator, ifnecessary. As illustrated in FIG. 3, the controller 100 includes abird's eye image synthesizing unit 110, a camera image switching/viewingpoint changing unit 120, an object position information generating unit130, a display control unit 150, a vessel image generating unit 140, anobject information collecting unit 210, and an object processing unit220.

The bird's eye image synthesizing unit 110 is connected to the imagecapturing devices 11 to 16 as illustrated in FIG. 3. The bird's eyeimage synthesizing unit 110 receives a plurality of image information(the first image information to the sixth image information) which arerespectively generated by the capturing of the respective imagecapturing devices 11 to 16. Then, the bird's eye image synthesizing unit110 synthesizes the images corresponding to the received plurality ofimage information and generates the bird's eye image 200 including theentire periphery of the dump truck 1. Specifically, the bird's eye imagesynthesizing unit 110 generates the bird's eye image information fordisplaying the bird's eye image 200, obtained by projecting a pluralityof images onto a predetermined projection plane, on the monitor 50 byrespectively changing the coordinates of the plurality of imageinformation. The bird's eye image information will be described later.

As illustrated in FIG. 3, the camera image switching/viewing pointchanging unit 120 is connected to the image capturing devices 11 to 16.Then, the camera image switching/viewing point changing unit 120switches the bird's eye image 200 and the images captured by therespective image capturing devices 11 to 16 and displayed on the screenof the monitor 50 in response to, for example, the obstacle detectionresult by the radar devices 21 to 28. Further, the camera imageswitching/viewing point changing unit 120 changes the image informationacquired by the respective image capturing devices 11 to 16 to the imageinformation from the viewing point of the upward infinity.

As illustrated in FIG. 3, the object position information generatingunit 130 is connected to the camera image switching/viewing pointchanging unit 120, the display control unit 150, and the objectprocessing unit 220. The object position information generating unit 130generates the object position information for synthesizing anddisplaying the object position information acquired by the radar devices21 to 28 in the bird's eye image 200 which is formed by synthesizing theimage information acquired by the respective image capturing devices 11to 16 and transmits the result to the camera image switching/viewingpoint changing unit 120 and the display control unit 150.

As illustrated in FIG. 3, the vessel image generating unit 140 isconnected to the display control unit 150. The vessel image generatingunit 140 generates information (first information P1) for displaying afirst vessel image showing the vessel 4 by partially excluding the rearside of the vessel 4 on the monitor 50 and information (secondinformation P2) for displaying a second vessel image showing the entirevessel 4 on the monitor 50 in the image of the vessel 4 of the dumptruck 1 illustrated in FIGS. 1 and 4. Then, the vessel image generatingunit 140 transmits at least one of the generated first and second vesselimages to the display control unit 150. The first vessel image and thesecond vessel image may display the front wheels 5 and the rear wheels 6of the dump truck 1 illustrated in FIG. 1. The first vessel image andthe second vessel image will be described later.

As illustrated in FIG. 3, the display control unit 150 is connected tothe bird's eye image synthesizing unit 110, the camera imageswitching/viewing point changing unit 120, the object positioninformation generating unit 130, and the vessel image generating unit140. The display control unit 150 generates the bird's eye image 200including the position of the object based on the object positioninformation in the entire periphery of the dump truck 1 obtained by theradar devices 21 to 28 and the bird's eye image information in theentire periphery of the dump truck 1 generated by the bird's eye imagesynthesizing unit 110. The image is displayed on the monitor 50.

Further, the display control unit 150 acquires at least one of the firstvessel image and the second vessel image generated by the vessel imagegenerating unit 140. Then, the display control unit 150 generates atleast one of a first bird's eye image 201 obtained by superimposing thefirst vessel image on the portion of the dump truck 1 of the bird's eyeimage 200 and a second bird's eye image 202 obtained by superimposingthe second vessel image on the portion of the dump truck 1 of the bird'seye image 200. The display control unit 150 displays any one of thegenerated first and second bird's eye images 201 and 202 on the monitor50. The display control unit 150 may switch the display of the firstbird's eye image 201 and the display of the second bird's eye image 202on the monitor 50. The first bird's eye image 201 and the second bird'seye image 202 will be described later.

As illustrated in FIG. 3, the display control unit 150 is connected withthe shift lever 37 and an image switching switch 39. The display controlunit 150 receives a signal transmitted from the shift lever 37 and theimage switching switch 39. For example, when the shift lever 37 ischanged to a reverse traveling mode, that is, the traveling mode of thedump truck 1 is changed to the reverse traveling mode, the displaycontrol unit 150 switches, for example, the image displayed on themonitor 50 to only the image (the image which captures the sixth area16C (FIG. 5) as the area extended toward the rear side of the vehiclebody portion 2) captured by the sixth image capturing device 16. Thatis, when the shift lever 37 is present at the neutral mode or theforward traveling mode, the first bird's eye image or the second bird'seye image and the image captured by any one of the image capturingdevices 11 to 16 are displayed in parallel on the monitor 50. However,in order to show the rear image of the dump truck 1 to the operator inthe reverse traveling mode, a single image is displayed on the monitor50 when the shift lever 37 is changed to the reverse traveling mode.Furthermore, when the shift lever 37 is present at the neutral mode orthe forward traveling mode, only the bird's eye image may be displayedon the monitor 50 and only any image may be displayed from the imagescaptured by the image capturing devices 11 to 16. Alternatively, themonitor 50 may display any two images in parallel from the bird's eyeimages and the images captured by the image capturing devices 11 to 16.The display on the monitor 50 may be switched in a manner such that theoperator operates a switch (not illustrated). The switch is connected tothe display control unit 150.

Further, for example, when the image switching switch 39 is operated byan operator (a service personnel instead of the operator when checkingor repairing a working vehicle) as an operator of the dump truck 1 so asto display the first bird's eye image 201, the display control unit 150switches the image displayed on the monitor 50 to the first bird's eyeimage 201. The image switching switch 39 is a push button type switch,and may be provided near the monitor 50 or the driver seat 31. It isdesirable that the installation position of the image switching switch39 be a position where the switch is easily touched by the operator'shand. Further, the monitor 50 may be a touch panel, and the imageswitching switch 39 may be operated by the contact of a finger on thetouch panel.

As illustrated in FIG. 3, the object information collecting unit 210 isconnected to the radar devices 21 to 28 and the object processing unit220. The object information collecting unit 210 receives the objectdetection result in the respective detection ranges of the radar devices21 to 28 and transmits the object detection result to the objectprocessing unit 220.

As illustrated in FIG. 3, the object processing unit 220 is connected tothe object information collecting unit 210 and the object positioninformation generating unit 130. The object processing unit 220transmits the object position information received from the objectinformation collecting unit 210 to the object position informationgenerating unit 130.

The controller 100 is configured by a combination of, for example, acomputer including a CPU (Central Processing Unit) as a calculationdevice and a memory as a storage device and an image processing device(for example, an image board) executing an image process such as asynthesis of the bird's eye image. The image processing device isequipped with, for example, an exclusive IC (for example, FPGA:Field-Programmable Gate Array) executing an image process such as asynthesis of the bird's eye image, a memory (for example, VRAM: VideoRandom Access Memory), and the like.

In the embodiment, as illustrated in FIG. 4, the image capturing devices11 to 16 are disposed at the front surface and the side surface of theupper deck 2 b and below the vessel 4. Then, the controller 100generates the bird's eye image 200 illustrated in FIG. 5 by synthesizingthe first image information to the sixth image information captured andacquired by the image capturing devices 11 to 16 and displays the resulton the monitor 50 which is disposed at the front side of the driver seat31 inside the cab 3. At this time, the monitor 50 displays an image suchas the bird's eye image 200 in response to the control of the controller100. The bird's eye image 200 may be obtained by the controller 100through the synthesizing of the first image information to the sixthimage information corresponding to the first area 11C to the sixth area16C captured by the image capturing devices 11 to 16. The peripherymonitoring system 10 displays the bird's eye image 200 on the monitor50. For this reason, the operator of the dump truck 1 may monitor theentire range of 360° in the periphery of the dump truck 1 by seeing thebird's eye image 200 displayed on the monitor 50. Next, the bird's eyeimage will be described.

<Generation of Bird's Eye Image>

FIG. 7 is a diagram illustrating an image switching method using avirtual projection plane VP. The controller 100 generates the bird's eyeimage 200 in the periphery of the dump truck 1 based on the plurality ofimages obtained by the first image information to the sixth image.Specifically, the controller 100 executes the coordinate conversion ofthe first image information to the sixth image information using thepredetermined conversion information item. The conversion information isthe information which represents the position coordinate of each pixelof the input image and the position coordinate of each pixel of theoutput image. In the embodiment, the input image is an image which iscaptured by the image capturing devices 11 to 16 and corresponds to thefirst image information to the sixth image information. The output imageis the bird's eye image 200 which is displayed on the monitor 50.

The controller 100 converts the images captured by the image capturingdevices 11 to 16 into the image seen from a predetermined virtualviewing point positioned above the dump truck 1 by using the conversioninformation. Specifically, as illustrated in FIG. 7, the images capturedby the image capturing devices 11 to 16 are projected onto apredetermined virtual projection plane VP, so that the images areconverted into the image seen from the virtual viewing point VIPpositioned above the dump truck 1. The conversion information representsthe virtual projection plane VP. The converted image is the bird's eyeimage displayed on the monitor 50. The controller 100 generates thebird's eye image 200 in the periphery of the dump truck 1 by projectingthe first image information to the sixth image information acquired fromthe plurality of image capturing devices 11 to 16 onto the predeterminedvirtual projection plane VP so as to synthesize the image information.

As illustrated in FIG. 5, the areas in the periphery of the dump truck 1captured by the respective image capturing devices 11 to 16 overlap eachother in the first overlapping area OA1 to the sixth overlapping areaOA6. The controller 100 displays, in the bird's eye image 200, theimages corresponding to the first image information to the sixth imageinformation from the image capturing devices 11 to 16 in the firstoverlapping area OA1 to the sixth overlapping area OA6 are disposed sothat two adjacent images overlap each other.

Specifically, the controller 100 displays the image of the first imageinformation from the first image capturing device 11 and the image ofthe third image information from the third image capturing device 13 inthe first overlapping area OA1 so as to overlap each other. Further, thecontroller 100 displays the image of the first image information fromthe first image capturing device 11 and the image of the second imageinformation from the second image capturing device 12 in the secondoverlapping area OA2 so as to overlap each other. Further, thecontroller 100 displays the image of the third image information fromthe third image capturing device 13 and the image of the fifth imageinformation from the fifth image capturing device 15 in the thirdoverlapping area OA3 so as to overlap each other. Further, thecontroller 100 displays the image of the second image information fromthe second image capturing device 12 and the image of the fourth imageinformation from the fourth image capturing device 14 in the fourthoverlapping area OA4 so as to overlap each other. Further, thecontroller 100 displays the image of the fifth image information fromthe fifth image capturing device 15 and the image of the sixth imageinformation from the sixth image capturing device 16 in the fifthoverlapping area OA5 so as to overlap each other. Further, thecontroller 100 displays the image of the fourth image information fromthe fourth image capturing device 14 and the image of the sixth imageinformation from the sixth image capturing device 16 in the sixthoverlapping area OA6 so as to overlap each other.

In this way, in a case where two image information are synthesized so asto overlap each other in the first overlapping area OA1 to the sixthoverlapping area OA6, a value obtained by multiplying the synthesisratio is added to the value of the first image information to the sixthimage information. The synthesis ratio is a value corresponding to eachof the first image information to the sixth image information, and isstored in the controller 100. For example, the synthesis ratio of thefirst image information is 0.5, and the synthesis ratio of the secondimage information is 0.5. In this way, the synthesis ratio is set foreach of the first image information to the sixth image. Since thesynthesis ratio is used, the plurality of image information is displayedin a manner that the first overlapping area OA1 to the sixth overlappingarea OA6 are averaged. As a result, abrupt changes in the color and thecontrast are suppressed, and hence the controller 100 may generate thenatural bird's eye image 200. The controller 100 generates the synthesisimage information for displaying the bird's eye image 200 synthesized asdescribed above, and outputs the synthesis image information to themonitor 50.

<Image Capturing Ranges of Respective Image Capturing Devices>

As illustrated in FIG. 2, in the dump truck 1, the first image capturingdevice 11, the second image capturing device 12, the third imagecapturing device 13, the fourth image capturing device 14, and the fifthimage capturing device 15 are disposed in the upper deck 2 b, and thesixth image capturing device 16 is disposed below the vessel 4 at therear end of the frame 2 f. In particular, the second image capturingdevice 12 and the third image capturing device 13 cover the area fromthe diagonally forward left and right sides of the vehicle body portion2 of the dump truck 1 to the left and right sides as the image capturingarea. Further, the fourth image capturing device 14 and the fifth imagecapturing device 15 cover the area from the left and right sides of thevehicle body portion 2 of the dump truck 1 to the diagonally backwardleft and right sides as the image capturing area. With such aconfiguration, the controller 100 synthesizes the first imageinformation and the sixth image information captured by the first imagecapturing device 11 and the sixth image capturing device 16, andgenerates the bird's eye image 200 covering the entire periphery of thedump truck 1, thereby monitoring the periphery of the dump truck 1.

Further, in the embodiment, as illustrated in FIG. 5, the adjacent imagecapturing devices 11 to 16 are disposed so that the first area 11C tothe sixth area 16C as the areas which may be captured by the imagecapturing devices 11 to 16 overlap each other at the adjacent portions.The controller 100 may monitor the entire periphery of 360° on the planeof the dump truck 1 by providing the connection line at the overlappingportions of the first area 11C to the sixth area 16C which may becaptured by the respective image capturing devices 11 to 16.Furthermore, in the bird's eye image 200, the connection line connectingthe first area 11C to the sixth area 16C adjacent to each other may beset to an arbitrary position in the overlapping range of the first area11C to the sixth area 16C.

<Image Displayed on Monitor>

The image which is displayed on the monitor 50 illustrated in FIGS. 2and 3 is the first bird's eye image 201 or the second bird's eye image202 described above. The first bird's eye image 201 or the second bird'seye image 202 is generated by the controller 100 illustrated in FIG. 3.More specifically, the first bird's eye image or the second bird's eyeimage is generated by combining the above-described first vessel imageand second vessel image with the bird's eye image 200 based on thebird's eye image information which is obtained by synthesizing the firstimage information to the sixth image information using the bird's eyeimage synthesizing unit 110. Here, the bird's eye image information isdescribed, and the first vessel image, the second vessel image, thefirst bird's eye image 201, and the second bird's eye image 202 aredescribed.

FIG. 8 is a conceptual diagram illustrating a bird's eye imageinformation 200I. The bird's eye image information 200I illustrated inFIG. 8 includes the information of the working vehicle area TR as thearea with the dump truck 1 and the information of the periphery area SRas the periphery area of the dump truck 1. As described above, thebird's eye image information 200I is generated from the imageinformation captured by the image capturing devices 11 to 16, that is,the first image information to the sixth image information. Since theimage capturing devices 11 to 16 are attached to the outside of the dumptruck 1, the area at the inside in relation to the lenses of the imagecapturing devices 11 to 16 is not captured. For this reason, the workingvehicle area TR of the bird's eye image information 200I does notinclude the image information of the dump truck 1 and the imageinformation of the periphery area SR. Accordingly, for example, when theimage based on the bird's eye image information 200I is displayed on themonitor 50, the portion of the working vehicle area TR of the displayedimage is displayed as, for example, a shadow.

In a case where the bird's eye image 200 is displayed on the monitor 50,for example, the controller 100 displays the bird's eye image 200 on themonitor based on the image information obtained by combining the imageinformation (where the information format is, for example, a bitmapformat) illustrating the top view of the dump truck 1 with the workingvehicle area TR of the bird's eye image information 200I. The bird's eyeimage 200 illustrated in FIG. 5 is obtained by displaying the imageinformation generated in this way is displayed on the monitor 50. Next,the first vessel image and the second vessel image will be described.

FIG. 9 is a diagram illustrating a first vessel image 200B1. FIG. 10 isa diagram illustrating a second vessel image 200B2. The reference sign Lin FIGS. 9 and 10 indicates the front side of the vessel 4 or the dumptruck 1, and the reference sign T indicates the rear side thereof. Thefirst vessel image 200B1 is an image based on the above-described firstinformation P1, and the above-described second vessel image 200B2 is animage based on the second information P2. The first vessel image 200B1is visualized by displaying, for example, the first information P1 onthe monitor 50. Similarly, the second vessel image 200B2 is visualizedby displaying, for example, the second information P2 on the monitor 50.In the embodiment, the first information P1 and the second informationP2 are, for example, image data based on a bitmap format, but theinformation items are not limited thereto. These pieces of informationmay be, for example, image data based on a vector format. Furthermore,the first vessel image 200B1 or the second vessel image 200B2 indicatesa front end 4L of the flange portion 4F at the front portion of thevessel 4. It is not essentially to display the front end 4L, but whenthe front end 4L is displayed, the shape of the entire deck (the vessel4 and the flange portion 4F) is illustrated.

The first vessel image 200B1 is an image that the vessel 4 in which therear side T of the dump truck 1 illustrated in FIGS. 1 and 4, that is, apart (the vessel rear portion) 4TP (the range indicated by the diagonalline illustrated in FIG. 9) near a rear end 4T of the vessel 4 isexcluded is displayed on, for example, the monitor 50. In theembodiment, a rear end 4T1 of the vessel 4 from which the vessel rearportion 4TP is excluded is present between the rear side T of the rearwheel 6 and the rear end 4T of the vessel 4 from which the vessel rearportion 4TP is not excluded yet. In the embodiment, the first vesselimage 200B1 may include at least the vessel 4 from which the vessel rearportion 4TP is excluded. For this reason, for example, the first vesselimage 200B1 may further include at least one of a part of the vehiclebody portion 2, a part of the cab 3, the inclined ladder 2 d, and thelike illustrated in FIG. 3.

The second vessel image 200B2 is an image in which the entire vessel 4included in the dump truck 1 illustrated in FIGS. 1 and 4 is displayedon, for example, the monitor 50. Accordingly, the second vessel image200B2 also displays the vessel rear portion 4TP which is not displayedin the first vessel image 200B1. In the embodiment, the second vesselimage 200B2 may include at least the entire vessel 4. For this reason,for example, the second vessel image 200B2 may further include at leastone of a part of the vehicle body portion 2, a part of the cab 3, theinclined ladder 2 d, and the like illustrated in FIG. 3.

The first vessel image 200B1 and the second vessel image 200B2 mayinclude at least the vessel 4. However, as illustrated in FIGS. 9 and10, the front wheels 5 and the rear wheels 6 of the dump truck 1illustrated in FIG. 1 may be further included, and may be displayedalong with the vessel 4. Next, a case will be described in which thefront wheels 5 and the rear wheels 6 are included in the first vesselimage 200B1 and the second vessel image 200B2. In this case, the entireimage of the front wheels 5 and the rear wheels 6 when seen from thedirection perpendicular to the respective rotation axes is displayed soas to overlap the first vessel image 200B1 and the second vessel image200B2. The image of the front wheels 5 and the rear wheels 6 has arectangular shape. Since the first vessel image 200B1 and the secondvessel image 200B2 illustrate the state where the dump truck 1 is seenfrom the upside, the front wheels 5 and the rear wheels 6 are displayedso as to transparently overlap the vessel 4.

Since at least a part of the front wheels 5 and the rear wheels 6 isdisplayed on the first vessel image 200B1 and the second vessel image200B2, the operator of the dump truck 1 may easily recognize thepositional relation between the front and rear wheels 5 and 6 and theobject (the subject) existing in the periphery of the dump truck 1. Thefront wheels 5 and the rear wheels 6 may be partially displayed.However, as in the embodiment, when all the front and rear wheels 5 and6 are displayed, the operator of the dump truck 1 may easily recognizethe existence of the front and rear wheels 5 and 6 and the positionalrelation between the front and rear wheels 5 and 6, the dump truck 1,and the vessel 4 compared to the case where only a part of them isdisplayed. The front wheels 5 and the rear wheels 6 may be distinguishedfrom the vessel 4 and may be displayed in a color different from that ofthe vessel 4 or in the same color as that of the vessel 4 withencircling the front wheels 5 and the rear wheels 6 using a line.

The front wheels 5 and the rear wheels 6 are displayed at a positionwhere the front wheels 5 and the rear wheels 6 are disposed when thedump truck 1 is seen from the bird's eye position. In the embodiment, aleft front wheel 5L is displayed at the left front side of the vessel 4,a right front wheel 5R is displayed at the right front side of thevessel 4, a left rear wheel 6L is displayed at the left rear side of thevessel 4, and a right rear wheel 6R is displayed at the right rear sideof the vessel 4. With such a configuration, the operator of the dumptruck 1 may easily recognize the relation between the dump truck 1, thevessel 4, the front wheels 5, and the rear wheels 6.

In a case where the front wheels 5 and the rear wheels 6 are displayed,it is desirable that the first vessel image 200B1 exclude the rear sidein relation to the end of the rear wheel 6 at the rear side of the dumptruck 1. With such a configuration, the first vessel image 200B1 maydisplay the entire rear wheel 6. Furthermore, in a case where the frontwheels 5 and the rear wheels 6 are displayed, the first vessel image200B1 excluding the vessel 4 from the front side in relation to the endof the rear wheel 6 at the rear side of the dump truck 1 is notexcluded. For example, the sixth image capturing device 16 whichcaptures the rear side of the dump truck 1 is disposed between thevessel 4, the left rear wheel 6L, and the right rear wheel 6R. For thisreason, the first vessel image 200B1 may exclude the vessel 4 at therear side of the dump truck 1 from the position of the sixth imagecapturing device 16. Further, the first vessel image 200B1 may excludethe vessel 4 at the rear side of the dump truck 1 from the positioncaptured by the sixth image capturing device 16. In this way, since thesixth image capturing device 16 may display the entire image capturingarea on the first bird's eye image 201 to be described later, theoperator of the dump truck 1 may more easily recognize the environmentin the periphery of the dump truck 1.

The actual dump truck 1 is set in consideration of the balance of theload (the weight of the vehicle body and the weight of the freight)applied to each tire. For this reason, in the dump truck 1, each frontwheel 5 is a single tire, and each rear wheel 6 is a double tire, thatis, a tire obtained by arranging two tires in parallel. For this reason,the rear wheels 6, that is, the left rear wheel 6L and the right rearwheel 6R may be displayed so that a plurality of (in the embodiment,two) vehicle wheels 6LO and 6LI and two vehicle wheels 6RO and 6RI arerespectively disposed at the left and right sides of the vessel 4. Withsuch a configuration, the operator of the dump truck 1 may easily andintuitively recognize the front and rear sides of the dump truck 1. Inthe embodiment, each of the left rear wheel 6L and the right rear wheel6R includes two tires in accordance with the actual dump truck 1, butthe number is not limited to two. Further, the width of the rear wheel 6may be displayed so as to be larger than the width of the front wheel 5.In addition, the front wheels 5 and the rear wheels 6 may berespectively displayed in different colors or the front wheels 5 may bedisplayed in a flickering manner. Even in this configuration, since theoperator of the dump truck 1 may distinguish the rear wheels 6 from thefront wheels 5, it is easy to intuitively recognize the front and rearsides of the dump truck 1.

For example, as described above, in a case where the monitor 50 isprovided so as to be suspended from the ceiling inside the cab 3 and themonitor 50 is provided at the right side (or the left side) of theoperator while the operator sits on the seat, the upper side of themonitor 50 does not match the front side of the dump truck 1. In such acase, it is considered that the operator of the dump truck 1 may notintuitively see the front and rear direction of either the first vesselimage 200B or the second vessel image 200B2 displayed on the monitor 50.In such a case, since all the front and rear wheels 5 and 6 aredisplayed, the operator may easily recognize the front and reardirection of the first vessel image 200B or the second vessel image200B2 displayed on the monitor 50.

In this way, since the operator of the dump truck 1 may distinguish therear wheels 6 and the front wheels 5 from each other by respectivelydisplaying the front wheels 5 and the rear wheels 6 in a differentmanner, it is easy to intuitively recognize the front and rear sides ofthe dump truck 1. Next, the first bird's eye image 201 and the secondbird's eye image 202 will be described.

FIG. 11 is a diagram illustrating an example of the first bird's eyeimage 201. FIG. 12 is a diagram illustrating an example of the secondbird's eye image 202. The first bird's eye image 201 is an imageobtained by superimposing the first vessel image 200B1 on the workingvehicle area TR of the bird's eye image 200. The second bird's eye image202 is an image obtained by superimposing the second vessel image 200B2on the working vehicle area TR of the bird's eye image 200. The firstbird's eye image 201 and the second bird's eye image 202 are alldisplayed and visualized on the monitor 50 by the controller 100. Sincethe first bird's eye image 201 and the second bird's eye image 202 maybe generated by synthesizing the first vessel image 200B1 or the secondvessel image 200B2 with the bird's eye image 200 in a superimposingmanner, the process load of the controller 100 may be reduced.

The first bird's eye image 201 and the second bird's eye image 202 areall generated by the display control unit 150 of the controller 100illustrated in FIG. 3, and are displayed on the monitor 50. The displaycontrol unit 150 generates a first synthesis image information 201I bythe combination of the bird's eye image information 200I generated bythe bird's eye image synthesizing unit 110 and the first information P1generated by the vessel image generating unit 140. Further, the displaycontrol unit 150 generates a second synthesis image information 202I bythe combination of the bird's eye image information 200I and the secondinformation P2 generated by the vessel image generating unit 140. Thefirst synthesis image information 201I is a piece of information fordisplaying the first bird's eye image 201 on the monitor 50 and thelike, and the second synthesis image information 202I is a piece ofinformation for displaying the second bird's eye image 202 on themonitor 50 and the like.

In the embodiment, the first bird's eye image 201 and the second bird'seye image 202 include a part of the vehicle body portion 2 of the dumptruck 1 and the inclined ladder 2 d in addition to the vessel 4. Thefirst bird's eye image 201 and the second bird's eye image 202 include apart of the vessel 4, the vehicle body portion 2, and the like and theperiphery of the dump truck 1, and these are displayed and visualized onthe monitor 50. The periphery of the dump truck 1 is the periphery of aleft side portion 4SL, the right side portion 4SR, and the rear ends 4T1and 4T of the vessel 4 and a front portion 2L of the vehicle bodyportion 2.

In the embodiment, in the first bird's eye image 201 and the secondbird's eye image 202, the dotted lines RL1, RL2, and RL3 are displayedin the periphery of the dump truck 1. The dotted line RL1 is displayedat a position closest to the dump truck 1, and the dotted line RL3 isdisplayed at a position farthest from the dump truck 1. The dotted lineRL2 is displayed between the dotted line RL1 and the dotted line RL3.The dotted lines RL1, RL2, and RL3 respectively indicate the positionsdistant from the dump truck 1 by a predetermined distance. The operatorof the dump truck 1 may recognize the distance between the dump truck 1and the object (for example, a person or a vehicle such as anautomobile) as the object displayed on the first bird's eye image 201 orthe second bird's eye image 202 by the dotted lines RL1, RL2, and RL3.

The sixth image capturing device 16 is disposed between the left rearwheel 6L and the right rear wheel 6R at the rear side of the dump truck1 so as to be positioned below the vessel 4. For this reason, since thesixth image capturing device 16 may capture a part of the lower side ofthe vessel, the bird's eye image information 200I illustrated in FIG. 8includes a part of the lower side of the vessel. The first bird's eyeimage 201 displays the vessel 4 from which the vessel rear portion 4TPis excluded. For this reason, the first bird's eye image 201 displaysthe lower area of the vessel rear portion 4TP captured by the sixthimage capturing device 16. On the contrary, in the second bird's eyeimage 202, the lower area of the vessel rear portion 4TP is hidden bythe vessel rear portion 4TP, but the entire rear end 4T of the vessel 4is displayed.

Since the first bird's eye image 201 also displays the lower area of thevessel rear portion 4TP, the operator of the dump truck 1 may recognizethe environment around the dump truck 1 in more detail. For this reason,when the controller 100 displays the first bird's eye image 201 on themonitor 50 before at least the dump truck 1 is started, the operator mayappropriately check the periphery environment. For example, in a casewhere an object at a height lower than the height of the vessel 4 existsbehind the rear wheel 6, it is possible to further reliably monitor theperiphery. The second bird's eye image 202 displays the entire rear end4T of the vessel 4. For this reason, in a case where an object existsbehind the vessel 4, the controller 100 displays the second bird's eyeimage 202 on the monitor 50, and hence the operator of the dump truck 1may easily recognize the positional relation between the rear end 4T ofthe vessel 4 and the object. In particular, this is advantageous whenthe dump truck 1 moves backward. For example, in a case where an objectat a height equal to or higher than the height of the rear end 4T of thevessel 4 exists in the periphery of the dump truck 1, it is possible tofurther reliably monitor the periphery.

The first bird's eye image 201 may display an image showing the lowerarea of the vessel rear portion 4TP and an image showing the outerperipheral portion of the vessel rear portion 4TP, that is, the rear end4T. In the example illustrated in FIG. 11, an image indicated by thedotted line is displayed at a portion corresponding to the outer frameof the vessel rear portion 4TP. With such a configuration, the operatorof the dump truck 1 may easily recognize the positional relation betweenthe rear end 4T of the vessel 4 and the object in a case where theobject exists behind the vessel 4. Furthermore, since the second bird'seye image 202 displays the entire vessel 4, it is considered that thepositional relation between the rear end 4T of the vessel 4 and theobject may be further easily recognized compared to the case where theouter peripheral portion of the vessel rear portion 4TP is displayed onthe first bird's eye image 201. Next, a control example of switching thedisplay of the first bird's eye image 201 and the display of the secondbird's eye image 202 will be described.

<Control Example of Switching First Bird's Eye Image and Second Bird'sEye Image>

FIG. 13 is a flowchart illustrating an example of switching the displayof the first image (the first bird's eye image 201 (the first vesselimage 200B1)) and the display of the second image (the second bird's eyeimage 202 (the second vessel image 200B2)). In this control example, thedisplay of the first image and the display of the second image areswitched on the monitor 50 based on at least one of the operation of theoperator of the dump truck 1 and the state of the dump truck 1. Morespecifically, it is possible to switch the display of the first vesselimage 200B1 as the first image and the second vessel image 200B2 as thesecond image displayed on the monitor 50. Furthermore, as describedabove, the display of the first bird's eye image 201 as the first imageand the display of the second bird's eye image 202 as the second imagemay be switched. Further, the periphery monitoring system 10 may furtherreliably monitor the periphery by causing the operator of the dump truck1 to recognize the environment in the periphery of the dump truck 1particularly before the dump truck 1 is started. In order to attain theobject, it is desirable that the controller 100 displays the firstbird's eye image 201 on the monitor 50 in principle and displays thesecond bird's eye image 202 on the monitor 50 when the condition ofswitching the display of the monitor 50 is satisfied. Accordingly, inthe embodiment, the first bird's eye image 201 is first displayed on themonitor 50, and when the condition of switching the display of themonitor 50 is satisfied, the controller 100 switches the display of themonitor 50 to the second bird's eye image 202.

When executing the control example, in step S101, the controller 100illustrated in FIG. 3 displays the first bird's eye image 201 on themonitor 50. Furthermore, when the dump truck 1 starts the internalcombustion engine (hereinafter, the engine), the first bird's eye image201 may be essentially displayed on the monitor 50. That is, when theengine is started by the operator who operates a key switch (notillustrated) for starting the engine of the dump truck 1, the controller100 receives the signal (the engine starting signal) of the key switchas a trigger signal, and the first bird's eye image 201 is displayed onthe monitor 50 instead of the second bird's eye image 202. Next, theroutine proceeds to step S102, and the display control unit 150 of thecontroller 100 executes the process of step S103 when the condition ofswitching the display of the monitor 50 is established (Yes in stepS102). In this case, the display control unit 150 of the controller 100switches the display of the monitor 50 from the first bird's eye image201 to the second bird's eye image 202. With such a configuration, instep S103, the second bird's eye image 202 is displayed on the monitor50.

When the condition of switching the display of the monitor 50 is notestablished (No in step S102), the display control unit 150 executes theprocess after step S101. That is, the display of the first bird's eyeimage 201 is continued on the monitor 50. In this way, the condition ofswitching the display of the monitor 50 in step S102 is the condition(the first condition) that switches the display of the monitor 50 fromthe first bird's eye image 201 to the second bird's eye image 202.

Next, the routine proceeds to step S104, and the display control unit150 of the controller 100 executes the process of step S105 when thecondition of switching the display of the monitor 50 is established (Yesin step S104). In this case, the display control unit 150 of thecontroller 100 switches the display of the monitor 50 from the secondbird's eye image 202 to the first bird's eye image 201. With such aconfiguration, in step S105, the monitor 50 displays the first bird'seye image 201.

When the condition of switching the display of the monitor 50 is notestablished (No in step S104), the display control unit 150 executes theprocess in step S103 and step S104. For this reason, the display of thesecond bird's eye image 202 is continued on the monitor 50. In this way,the condition of switching the display of the monitor 50 in step S104 isthe condition (the second condition) for switching the display of themonitor 50 from the second bird's eye image 202 to the first bird's eyeimage 201. Next, the condition for switching the display of the monitor50, more specifically, the first condition and the second condition willbe described.

(Condition for Switching Display of Monitor)

In the condition (which is appropriately referred to as the imageswitching condition) for switching the display of the monitor 50, thefirst condition is defined as the condition based on the operation ofthe operator who operates the dump truck 1. As such an example, forexample, the operator switches the display of the monitor 50 accordingto his/her intension. As an example, the operator operates the imageswitching switch 39 illustrated in FIG. 3 so that the display of themonitor 50 is switched from the first bird's eye image 201 to the secondbird's eye image 202. Then, the image switching switch 39 generates asignal for displaying the second bird's eye image 202 on the monitor 50.In step S103, the display control unit 150 of the controller 100 whichreceives the signal switches the display of the monitor 50 from thefirst bird's eye image 201 to the second bird's eye image 202.

In the image switching condition, the second condition is defined as thecondition based on the operation of the operator who operates the dumptruck 1 and the state of the dump truck 1. In a case of the secondcondition based on the operation of the operator, the operator switchesthe display of the monitor 50 according to his/her intension as in thefirst condition. As an example, the operator operates the imageswitching switch 39 illustrated in FIG. 3 so as to switch the display ofthe monitor 50 from the second bird's eye image 202 to the first bird'seye image 201. Then, the image switching switch 39 generates a signalfor displaying the first bird's eye image 201 on the monitor 50. In stepS105, the display control unit 150 of the controller 100 which receivesthe signal switches the display of the monitor 50 from the second bird'seye image 202 to the first bird's eye image 201.

In a case of the second condition based on the state of the dump truck1, for example, the speed (the running speed) at which the dump truck 1runs may become a predetermined threshold value or less. The runningspeed includes both running speeds in the forward and backward travelingmodes of the dump truck 1. The predetermined threshold value alsoincludes 0. Since the periphery monitoring system 10 causes the operatorto recognize the state in the periphery of the dump truck 1 particularlybefore the dump truck 1 is started, it is desirable that thepredetermined threshold value is set to the value at which the dumptruck 1 almost stops, but the invention is not limited thereto.

The display control unit 150 of the controller 100 acquires the runningspeed of the dump truck 1 from a control device (not illustrated) whichcontrols the operation of the dump truck 1. The running speed of thedump truck 1 may be detected by a vehicle speed sensor (notillustrated). Then, when the acquired running speed is a predeterminedthreshold value or less, in step S105, the display control unit 150switches the display of the monitor 50 from the second bird's eye image202 to the first bird's eye image 201. With such a configuration, whenthe dump truck 1 is stopped, the first bird's eye image 201 may bereliably displayed on the monitor 50. As a result, since the operatormay recognize the state in the periphery of the dump truck 1 includingthe lower state of the vessel rear portion 4TP in more detail before thedump truck 1 is started, it is possible to further reliably realize theperiphery monitoring.

Further, in a case of the second condition based on the state of thedump truck 1, for example, the object detection device may detect theobject existing behind the dump truck 1 as the object. The objectdetection device which detects the object existing behind the dump truck1 is, for example, at least one of the fifth radar device 25, the sixthradar device 26, the seventh radar device 27, and the eighth radardevice 28 illustrated in FIG. 6. Furthermore, the second condition mayinclude a case where one object is detected as the object by two radardevices in accordance with the position of the object.

When the display control unit 150 of the controller 100 acquires aninformation that an object exists behind the dump truck 1 from theobject position information generating unit 130 illustrated in FIG. 3,in step S105, the display control unit switches the display of themonitor 50 from the first bird's eye image 202 to the first bird's eyeimage 201. With such a configuration, when an object exists behind thedump truck 1, the vessel rear portion 4TP is not displayed on themonitor 50, and hence the operator may check the lower state of thevessel rear portion 4TP. As a result, since the operator may recognizethe state in the periphery of the dump truck 1 when starting the dumptruck 1 in more detail, it is possible to further reliably realize theperiphery monitoring.

Further, in a case of the second condition based on the state of thedump truck 1, for example, the traveling mode of the dump truck 1 may beset as the backward traveling mode. This is a case in which, forexample, the shift lever 37 illustrated in FIG. 3 is operated to thebackward traveling mode by the operator of the dump truck 1. Forexample, when the shift lever 37 is operated to the backward travelingposition, a signal for switching the traveling mode of the dump truck 1to the backward traveling mode is generated. In step S105, the displaycontrol unit 150 of the controller 100 which receives the signalswitches the display of the monitor 50 from the second bird's eye image202 to the first bird's eye image 201. As a result, since the operatormay recognize the state in the periphery of the dump truck 1 includingthe lower state of the vessel rear portion 4TP in more detail beforemoving the dump truck 1 backward, it is possible to further reliablyrealize the periphery monitoring. Furthermore, when the traveling modeof the dump truck 1 is set as the forward traveling mode, the display ofthe monitor 50 may not be switched from the second bird's eye image 202to the first bird's eye image 201. In this case, when the monitor 50displays the second bird's eye image 202, the state is maintained.

As described above, in the embodiment, the controller 100 which isincluded in the periphery monitoring system 10 may switch the display ofthe first image (at least one of the first vessel image 200B1 and thefirst bird's eye image 201) and the display of the second image (atleast one of the second vessel image 200B2 and the second bird's eyeimage 202) with respect to the monitor 50. For this reason, since theperiphery monitoring system 10 may switch the first bird's eye image 201to the second bird's eye image 202 by the operation of the operator ofthe dump truck 1 so that the second bird's eye image is displayed on themonitor 50, the operator may check the image which may be easilyunderstood by the operator through the monitor 50. Further, the operatormay easily intuitively recognize the relation between the dump truck 1and the object existing therearound. In this way, the peripherymonitoring system 10 according to the embodiment may provide an imagewhich may be easily understood by the operator.

Further, in the embodiment, the controller 100 which is included in theperiphery monitoring system 10 displays the first bird's eye image 201on the monitor 50 in principle. Then, the controller 100 displays thesecond bird's eye image 202 on the monitor 50 when there is an operationof the operator. With such a configuration, it is possible to displaythe image according to the operator's intention on the monitor 50.Further, in the embodiment, since the first bird's eye image 201excluding the vessel rear portion 4TP and displaying the lower side ofthe vessel rear portion 4TP is displayed on the monitor 50 in principle,there is an advantage that the range causing the operator to check theperiphery using the monitor 50 is extended in the normal state. In theembodiment, the first bird's eye image 201 is displayed on the monitor50 in principle, but the second bird's eye image 202 may be displayed onthe monitor 50 in principle. However, as described above, it isdesirable that the first bird's eye image 201 is displayed on themonitor 50 in principle so that the operator may recognize the state inthe periphery of the dump truck 1 in more detail.

Further, in the embodiment, the controller 100 which is included in theperiphery monitoring system 10 also displays the front wheels 5 and therear wheels 6 of the dump truck 1 on the first bird's eye image 201 andthe second bird's eye image 202. For this reason, since the operator ofthe dump truck 1 may easily recognize the relation between the positionsof the front wheels 5 and the rear wheels 6 and the object existing inthe periphery of the dump truck 1, it is possible to further reliablymonitor the periphery. In particular, in a case where the vessel rearportion 4TP is excluded from the vessel 4, when the rear wheel 6 isdisplayed, the operator may recognize the object existing behind therear wheel 6 by the relation with respect to the rear wheels 6, andhence it is easy to recognize the object at an early timing by theappropriate relative positional relation. In this way, since theperiphery monitoring system 10 displays the front wheels 5 and the rearwheels 6 on the first bird's eye image 201 and the second bird's eyeimage 202, it is possible to provide an image which may be easilyunderstood by the operator of the dump truck 1 when the runningoperation is assisted by the bird's eye image synthesized with theimages captured by the plurality of image capturing devices.

Further, in the embodiment, the controller 100 which is included in theperiphery monitoring system 10 displays the front wheels 5 and the rearwheels 6 on the monitor 50 in a different manner. With such aconfiguration, since the operator of the dump truck 1 may easilydetermine the front and rear sides of the dump truck 1, it is easy tointuitively recognize the relation between the dump truck 1 operated bythe operator and the object existing therearound. Particularly, when themonitor 50 is disposed at the lateral side instead of the front side ofthe operator due to the layout inside the cab 3, the operator needs tocheck the monitor 50 by directing his/her head toward the monitor 50. Insuch a case, the operator may not easily recognize the direction of thedump truck 1. However, as in the embodiment, when the front wheel 5 andthe rear wheel 6 are displayed on the monitor 50 in a different manner,there is an advantage that the operator may easily and reliablyrecognize the front and rear sides of the dump truck 1.

The periphery monitoring system 10 uses the wide dynamic camera as theimage capturing devices 11 to 16. For this reason, the image capturingdevices 11 to 16 may brightly correct a dark portion like a shadow ofthe dump truck 1 while keeping a level at which the bright portion maybe seen. Accordingly, black saturation and white-out do not easily occurin the images captured by the image capturing devices 11 to 16, andhence the images may be easily understood as a whole. As a result, theperiphery monitoring system 10 which includes the image capturingdevices 11 to 16 may display the first bird's eye image 201 or thesecond bird's eye image 202 in which an object such as a vehicleexisting in the area as the shadow of the dump truck 1 is easily seen onthe monitor 50. In this way, the periphery monitoring system 10 maydisplay the object in the periphery of the dump truck 1 on the firstbird's eye image 201 or the second bird's eye image 202 even in anenvironment in which the contrast difference in contrast is large whenmonitoring the periphery of the dump truck 1 by using the imagescaptured by the image capturing devices 11 to 16. As a result, theoperator of the dump truck 1 may reliably see the object existing in theperiphery of the dump truck 1, particularly, the area as the shadowregardless of the environment.

In this way, since the periphery monitoring system 10 may generate thefirst bird's eye image 201 and the second bird's eye image 202 thatreliably display the object in the periphery of the dump truck 1 even inan environment in which the contrast difference in contrast is large, itis possible to reliably see the object existing in the dead angle of theoperator by the first bird's eye image 201 or the second bird's eyeimage 202. Accordingly, the periphery monitoring system 10 is veryeffective when monitoring the periphery of the above-describedsuperjumbo dump truck 1 used in a mine. That is, there is a case inwhich the dump truck 1 may form an area as a very large shadow and movewhile forming an area as a shadow. In this case, the area as the shadowlargely changes due to the elevation of the vessel 4 and the area as thedead angle is large. The periphery monitoring system 10 generates thefirst bird's eye image 201 or the second bird's eye image 202 whichreliably displays the object in the periphery of the dump truck 1 insuch the dump truck 1 and hence provides an accurate information item onthe periphery of the dump truck 1 for the operator of the dump truck 1.Further, the periphery monitoring system 10 may provide accurateinformation on the periphery of the dump truck 1 for the operator of thedump truck 1 in a case of the dump truck 1 which is operated in a placewhere the illuminance difference between a sunny area and a shadow areais very large as in the equatorial zone.

While the embodiment has been described, the embodiment is not limitedto the above-described content. Further, the above-describedconstituents include a constituent that is easily supposed by the personskilled in the art, a constituent that has substantially the sameconfiguration, and a constituent that is included in a so-calledequivalent scope. Further, the above-described constituents may beappropriately combined with each other. Furthermore, the constituentsmay be omitted, replaced, or modified in various forms in the scopewithout departing from the gist of the embodiment.

REFERENCE SIGNS LIST

-   -   1 DUMP TRUCK    -   2 VEHICLE BODY PORTION    -   2L FRONT PORTION    -   2 c, 2 d LADDER    -   2 e GUARDRAIL    -   2 f FRAME    -   3 CAB    -   4 VESSEL    -   4T, 4T1 REAR END    -   4TP VESSEL REAR PORTION    -   5 FRONT WHEEL    -   6 REAR WHEEL    -   6LI, 6LO, 6RI, 6RO VEHICLE WHEEL    -   10 WORKING VEHICLE PERIPHERY MONITORING SYSTEM (PERIPHERY        MONITORING SYSTEM)    -   11, 12, 13, 14, 15, 16 IMAGE CAPTURING DEVICE    -   21, 22, 23, 24, 25, 26, 27, 28 RADAR DEVICE    -   31 DRIVER SEAT    -   39 IMAGE SWITCHING SWITCH    -   50 MONITOR    -   100 CONTROLLER    -   110 BIRD'S EYE IMAGE SYNTHESIZING UNIT    -   120 CAMERA IMAGE SWITCHING/VIEWING POINT CHANGING UNIT    -   130 OBJECT POSITION INFORMATION GENERATING UNIT    -   140 VESSEL IMAGE GENERATING UNIT    -   150 DISPLAY CONTROL UNIT    -   210 OBJECT INFORMATION COLLECTING UNIT    -   220 OBJECT PROCESSING UNIT

1. A working vehicle periphery monitoring system that monitors aperiphery of a working vehicle including a vehicle body frame whichsupports front and rear wheels and a vessel which protrudes toward arear side of the vehicle body frame than the rear wheels to load freightthereon, the working vehicle periphery monitoring system comprising: aplurality of image capturing devices each of which is attached to theworking vehicle and captures the periphery of the working vehicle tooutput a piece of image information; a bird's eye image synthesizingunit that acquires a plurality pieces of the image information andsynthesizes the acquired image information to generate bird's eye imageinformation for displaying a bird's eye image of the working vehicle andthe periphery of the working vehicle on a display device; and a displaycontrol unit that displays, on the display device, at least one of afirst image obtained by superimposing a first vessel image including atleast the vessel other than a part of the vessel at the rear side of theworking vehicle on an area in which the working vehicle is present inthe bird's eye image and a second image obtained by superimposing asecond vessel image including at least all of the vessel on the area inwhich the working vehicle is present in the bird's eye image.
 2. Theworking vehicle periphery monitoring system according to claim 1,wherein the display control unit switches the display of the first imageand the display of the second image based on an operation of an operatorthat operates the working vehicle.
 3. The working vehicle peripherymonitoring system according to claim 1, wherein the display control unitswitches the display of the first image and the display of the secondimage according to a state of the working vehicle.
 4. The workingvehicle periphery monitoring system according to claim 3, wherein thedisplay control unit switches the display of the first image and thedisplay of the second image based on a running speed of the workingvehicle.
 5. The working vehicle periphery monitoring system according toclaim 3, wherein the working vehicle includes an object detection devicethat detects an object existing behind the working vehicle, and whereinthe display control unit switches the display of the first image and thedisplay of the second image when the object detection device detects theobject.
 6. The working vehicle periphery monitoring system according toclaim 3, wherein the display control unit switches the display of thefirst image and the display of the second image when a traveling mode ofthe working vehicle becomes a reverse traveling mode.
 7. A workingvehicle periphery monitoring system that monitors a periphery of aworking vehicle including a vehicle body frame which supports front andrear wheels and a vessel which protrudes toward a rear side of thevehicle body frame than the rear wheels to load freight thereon, theworking vehicle periphery monitoring system comprising: a plurality ofimage capturing devices each of which is attached to the working vehicleand captures the periphery of the working vehicle to output a piece ofimage information; a bird's eye image synthesizing unit that acquires aplurality pieces of the image information and synthesizes the acquiredimage information to generate bird's eye image information fordisplaying a bird's eye image of the working vehicle and the peripheryof the working vehicle on a display device; and a display control unitthat displays, on the display device, at least one of a first imageobtained by superimposing a first vessel image including at least thevessel other than a part of the vessel at the rear side of the workingvehicle on an area in which the working vehicle is present in the bird'seye image and a second image obtained by superimposing a second vesselimage including at least all of the vessel on the area in which theworking vehicle is present in the bird's eye image, wherein the displaycontrol unit switches the display according to an operation of anoperator that operates the working vehicle or a state of the workingvehicle.
 8. The working vehicle periphery monitoring system according toclaim 7, wherein the first vessel image includes the front and rearwheels displayed with the vessel, and the second vessel image includesthe front and rear wheels displayed with the vessel.
 9. The workingvehicle periphery monitoring system according to claim 8, wherein thedisplay control unit displays all of the front and rear wheels.
 10. Theworking vehicle periphery monitoring system according to claim 8,wherein as the rear wheels, a plurality of vehicle wheels are displayedat each of left and right sides of the vessel.
 11. The working vehicleperiphery monitoring system according to claim 8, wherein in the firstvessel image, a rear side of the vessel than an end of the rear wheel atthe rear side of the working vehicle is excluded.
 12. A working vehiclecomprising: the working vehicle periphery monitoring system according toclaim
 7. 13. The working vehicle periphery monitoring system accordingto claim 1, wherein the first vessel image includes the front and rearwheels displayed with the vessel, and the second vessel image includesthe front and rear wheels displayed with the vessel.
 14. The workingvehicle periphery monitoring system according to claim 13, wherein thedisplay control unit displays all of the front and rear wheels.
 15. Theworking vehicle periphery monitoring system according to claim 13,wherein as the rear wheels, a plurality of vehicle wheels are displayedat each of left and right sides of the vessel.
 16. The working vehicleperiphery monitoring system according to claim 13, wherein in the firstvessel image, a rear side of the vessel than an end of the rear wheel atthe rear side of the working vehicle is excluded.
 17. A working vehiclecomprising: the working vehicle periphery monitoring system according toclaim 1.